It doesn't matter what wilderness environment you're in, having a basic knowledge of signaling can give you a tremendous advantage towards being rescued in a survival situation. It can make the critical difference of being seen by your rescuers or not.
Whenever you are trying to signal remember this, your signal is only effective as long as it can be seen by someone. If you are in a sheltered area, this might mean you will have to move to a more open area. Your signal is only as good as its visibility.
You should always carry some sort of signaling device with you in your kit. Signal mirrors are the ultimate tool for signaling. They are light to carry and a flash from a mirror can be seen from miles away in good conditions. Carrying a whistle is also good for short distance signaling. There are many different devices you can buy for signaling, you will have to decide what is best suited for you and the environment you're in.
Improvising is the key to signaling when you don't have a specific tool for the job. Anything shiny can be used for a reflection signal. This could be a CD, knife blade, a watch, or aluminum can. If you are within sight of your rescuers waving a piece of clothing can be an excellent way of gaining their attention. Improvising a signal is only limited by your imagination.
Signal fires are frequently thought of as a good reliable source for signaling. While I would say that signal fires are a good supplementary signal, they should not be counted on as your only signal. Using a signal fire at night is an excellent idea, as the flames can be seen from a very long distance away. Weather conditions must be good for the fire to be effective during the daytime. For a signal fire to give an accurate signal of where you are you must have very little or no wind. Other wise the smoke will dissipate and form a cloud of smoke over a very large area. Another reason signal fires should not be relied upon as the sole source of signaling is the construction of the fire. If you are injured, building and lighting a signal fire can be an impossible task.
Ground to air signals can be good for getting attention from search and rescue. There are many different ground to air signals conveying many different messages. Making a large SOS is an internationally recognized signal for help. If you would ever have to self rescue, make a large arrow indicating the direction you are traveling. This gives search and rescue a definite direction to search in.
Series of three are a internationally recognized signal for help. If you are making a ground to air signal this could be three piles of rocks in the shape of a triangle. At night you could use three fires in the same fashion. If you are doing repeated signals, do three signals then wait one minute then do three more and continue on in this way. Using these signals any other time then in an emergency is prohibited by law.